Control mechanism for pressing machines



Sept. 5, 1939. G. w JOHNSON CONTROL MECHANISM FOR PRESSING MACHINESOriginal Filed Aug. 7, 1937 2 Sheets-Sheet 1 N 0; IT J mw mE ATTO p 5,1939- Q G. w. JOHNSON 2,171,568

CONTROL MECHANISM FOR PRESSING MACHINES Original Filed Aug. 7, 1937 2Sheets-Sheet 2 FIG.--3

- INVENTOR GEORGE W. JOHNSON Patented Sept. 5, 1939 UNITED STATES PATENTOFFICE CONTROL MECHANISM FOR PRESSING MACHINES Ohio Application August7, 1937, Serial No. 157,825 Renewed November 26, 1938 9 Claims.

This invention relates to improvements in control mechanism for pressingmachines.

While my improved control mechanism may be applied to any type of presshaving coacting platens, it is particularly applicable to a press of thetype used for laundry and garment work.

One of the features of the present invention is the provision of asafety two-hand control for keeping the operators hands occupied duringthe closing movement of the press and the arrangement of the twocontrols or manuals for a two-stage movement, the first stagecorresponding to movement of the pressing members to a safe closedposition and the second stage of 151 manual movement corresponding tothe final closing of the press. My invention relates to a novelarrangement of a pair of control manuals wherein both manuals must beactuated coincidently to produce press closure. The two manuals 20 areconnected by a whifiletree or equalizer bar in such a manner thatactuation of both manuals is necessary to operate a press controlmember. This equalizer bar is of a resilient type and arranged in anovel manner so that during the first 25 stage of manual movement it iseiiective to return the manuals to unoperated position and during thesecond stage of manual movement it is effective to move the manuals intofinal operated position and to hold them there.

30 The novel features of my invention will be apparent from theaccompanying drawings and specification and the essential features willbe summarized in the claims.

In the drawings, Fig. 1 is an end elevation of 35 a pressing machineembodying my invention with the press parts in open position; Fig. 2 isa diagrammatic layout of the control mechanism for the pressing machinewith the parts in the position corresponding to the press of Fig. 1;Fig. 3

4.0 is a view of the pressing machine showing the position of the pressparts in full lines in safe closed position and in dot-dash lines infully closed position; while Fig. lis a diagram of the control mechanismsimilar to Fig. 2 but showing 45- in full lines the position of thecontrol parts corresponding to the full line position of the press partsof Fig. 3 and .in dot-dash lines showing the position of the controlparts corresponding to the dot-dash position of the press parts of Fig.3.

50 My invention is applicable to various types of presses but I haveillustrated a press having a frame It supporting a pressing bed H and apivoted yoke l2 by means of which a pressing head 53 is oscillatableiromthe open position of Fig. 1

55 to the closed position of Fig. 3. A spring M normally maintains thehead in open position and toggle mechanism l5 actuated by motor it:moves the head into pressure engagement with the bed.

The motor I 6 is of the cylinder and piston type through which fluid issupplied from supply line 5 il through valve l8 and line l9. Valve I8has a normally closed inlet port I 8a and a normally open outlet port18b and a stem E80 by which the valve is actuated. For valve actuation adiaphragm motor 20 is provided having a piston 20a 10 operable bydiaphragm 23b to actuate the valve stem I80. The parts are normallybiased to the position of Fig. 2 by the spring 238. Pressure fluid issupplied back of diaphragm 2th through the conduit 2|, supply for whichis through conduit 22 and pilot valve 23. This pilot valve has an inletport 2311 closed by the ball 231), an exhaust port 23c and a valve stem2301. The pilot valve is actuated by means of pin 24 which is connectedintermediate the ends of a whifiietree or equalizer bar 25, the oppositeends of which are connected by toggle mechanisms 26 and 27 with manuals213 and 29. Stop pins 38 limit the movement of the manuals in theunoperated position of Fig. 2.

A movable stop member 3! lies between the toggle mechanisms 26 and 21when the press is open. The stop member 3i is a part of a bellcrankmember 32 pivoted to the press frame at 33. The lower arm of thebellcrank is pivotally connected with rod 34 which carries rigid with itthe collars 35 and 36. The rod as shown passes through a bracket 3'! onthe toggle mechanism 15. A spring 38 biases the bellcrank 32 and thestop 3! to the position shown in Figs. 1 and 2 and in full lines in Fig.3. 35

The equalizer bar 25 is resilient and preferably is a piece of springmetal convex toward the pilot valve as indicated in Fig. 2. Theresilience of this equalizer bar is utilized to hold the manuals 28 and29 in both the unoperated position of Fig. 2 40 and the fully operatedposition of Fig. 4, as will hereinafter appear.

In the operation of the press, work is arranged on the bed l i and theoperator actuates manuals 28 and 29 until the toggles 26 and 2? reach alimiting position against the stop member 3i as in dicated in full linesin Fig. 4. It will be noted that there is a lost motion between the pin24 and the valve stem 23d'so arranged that actuation of either of themanuals alone will take up this lost motion but will not move ball 23bfrom the valve seat 23a. It is necessary to produce coincidentalactuation of the two manuals to move the ball from its seat as indicatedin Fig. 4.

In this position of the parts the shoulder 23c on the valve stem hasengaged the exhaust valve seat 230 and the resilient equalizer bar 25has been flexed toward the left as viewed in Fig. 4. In this position ofthe parts if either or both of the manuals are released the energystored in the flexed bar 25 will return the manuals to the unoperatedposition of Fig. 2. When the manuals have reached the full line positionof Fig. 4, valve 23 is actuated, permitting a flow of pressure fluidthrough conduits I? and 22, valve 23 and conduit 2! to diaphragm motor29. This motor makes a stroke toward the left as shown in Fig. i,actuating valve i8 and admitting pressure fluid through line ll, valvel8 and line I!) to motor It so as to actuate the press in closingdirection, bringing the head down to the full line position of Fig. Inthis position of the parts it is no longer possible or likely that anoperator will be able to place a hand between the pressing members withsubsequent injury. When the press has reached this safe closed positionthe bracket 37 engages the collar 36 exerting a pull on rod 34 againstthe bias of spring 38, moving the bellcrank 32 from the full line to thedot-dash position of Fig. 3. This moves the stop member 3! downwardlyfrom between the toggles 26 and 21, permitting further actuation ofmanuals 28 and 29 to the dot-dash position of Fig. 4. It will be notedthat the toggles 26 and 27 thus pass from an over-center position wherethey tend to move outwardly to an over-center position where they tendto move inwardly. As the toggles move toward the dot-dash position ofFig. 4 and pass over their center line position, the energy stored inspring bar 25 is effective to continue the movement of the toggles 25and 2? inwardly until they reach the limit stop 39 and thereafter thespring bar 25 holds the toggles and the manuals in fully actuatedposition. This maintains valve 23 open which in turn through motor 2i!holds valve l8 open, supplying fluid to motor l6 and holding the pressclosed. To release the press one or both of the manuals 28 or 293 isreturned to the position of Fig. 2, whereupon all of the parts return tothe position of Fig. 2, and the press is opened by the spring 64. Aspring is shown for returning the ball valve 2% to its seat although theair pressure against it is sufiicient to perform this function if thevalve is horizontal. As the press opens, spring 38 is efiective toreturn the stop 3! between the toggles 2t and 21, thus completing thebreaking of these toggles outwardly and positioning the parts foranother press operation.

What I claim is:

1. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, controlmechanism including a control member for said power means, a pair ofmanuals spaced to require a hand of the operator on each for theircoincidental actuation, a resilient equalizer bar between said manualsadapted to return them to unactuated position, said bar having anoperative connection with said control member requiring coincidentalactuation of both of said manuals for efiective actuation of saidcontrol member, said manuals being arranged to stress said equalizer barupon actuation of said control member, and an operative connectionbetween said bar and manuals for holding said manuals in actuatedposition by said stress in said bar.

2. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, controlmechanism including a control member for said power means, manual meansrequiring both hands of the operator for actuation thereof, operatingconnections between said manual means and said control member includinga resilient bar and toggle means connected with said manual means, saidtoggle means being arranged for movement over-center when said controlmember is actuated, said bar being arranged for flexure when saidcontrol member is actuated, and said bar and toggle means being soconstructed and arranged that said bar in flexed position holds saidtoggle means in over-center position.

3. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, controlmechanism including a control member for said power means, a pair ofmanuals spaced to require a hand of the operator on each for theircoincidental actuation, a resilient equalizer bar having an operativeconnection with said control member intermediate its ends, operativeconnections between the ends of said bar and said manuals, at least oneof said last named connections comprising a toggle movable to oppositesides of its central fully-extended position by manual manipulation, andthe parts being so arranged that said bar is flexed by movement of saidtoggle sufficient to move said control member to actuated position,whereby the resilience of said flexed bar is operative to hold saidtoggle in either of its ofi-center positions.

4. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, controlmechanism including a control member for said power means, a pair ofmanuals spaced to require a hand of the operator on each for theircoincidental actuation, a resilient equalizer bar having an operativeconnection with said control member intermediate its ends, operativeconnections between the ends of said bar and said manuals, at least oneof said last named connections comprising a toggle movable to oppositesides of its central fully-extended position by manual manipulation, theparts being so arranged that said bar is flexed by movement of saidtoggle sufiicient to move said control member to actuated position,whereby the resilience of said flexed bar is operative to hold saidtoggle in either of its offcenter positions, said parts being arrangedto lie normally with said control member in unactuated position, meansnormally preventing movement of said toggle over center, and means forremoving said last named means responsive to movement Of the pressingmachine to a safe-closed position.

5, In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, controlmechanism including a control member for said pow-er means, a pair ofmanuals spaced to require a hand of the operator on each for theircoincidental actuation, a resilient equalizer bar having intermediateits ends an operative connection with said control member, togglesconnecting the ends of said bar with said manuals, each toggle beingmovable to opposite sides of its central fully-extended position bymanipulation of its associated manual, the parts including said togglesand equalizer bar and control member being arranged to requirecoincidental actuation of both of said manuals for effective actuationof said control member, and said parts being so arranged that said baris flexed by movement of said toggles sufficient to move said controlmemher to actuated position, whereby the resilience of said flexed baris operative to hold said toggles in either of their off-centerpositions.

6. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, controlmechanism including a control member for said power means, a pair ofmanuals spaced to require a hand of the operator on each for theircoincidental actuation, a resilient equalizer bar having intermediateits ends an operative connection with said control member, togglesconnecting the ends of said bar with said manuals, each toggle beingmovable to opposite sides of its central fully-extended position bymanipulation of its associated manual, the parts including said togglesand equalizer bar and control member being arranged to requirecoincidental actuation of both of said manuals for effective actuationof said control member, said parts being so arranged that said bar isflexed by movement of said toggles sufiicient to move said controlmember to actuated position, whereby the resilience of said flexed baris operative to hold said toggles in either of their ofi-centerpositions, said parts being arranged to lie normally with said controlmember in unactuated position, means normally preventing movement ofsaid toggles over center, means for removing said last named meansresponsive to movement of the pressing machine to a safe-closedposition, and stop means holding said toggles in extended position afterthey have moved slightly over center, whereby said control member isheld in actuated position.

'7. In a pressing machine having a pair of coacting pressing members,power means for causing a pressing operation between them, meansnormally tending to return said members to open position, and a controlmember normally in unactuated position and when actuated adapted tocause press-closing operation of said power means, the combination of apair of manuals spaced to require a hand of the operator on each of themfor their coincidental actuation, a resilient equalizer bar havingintermediate its ends an operative connection with said control member,a pair of toggles, one operatively connected between each manual and anend of said equalizer bar in such a manner that said bar normally holdssaid toggles on one side of central straightened position, the partsincluding said toggles and equalizer bar and control member being soarranged as to require coincidental movement of both of said toggles tosemi-straightened position for eifective actuation of said controlmember, block means effective in all positions of said pressing membersbetween open and safe-closed position to stop said toggles short ofstraightened position but sufliciently straightened to actuate saidcontrol member, whereby said equalizer bar is flexed and the energystored therein is available to break said toggles if said manuals arereleased, means responsive to movement of the press parts to safe-closedposition for removing said block means, whereupon continued actuation ofthe manuals by the operator is effective to move said togglesover-center, and stop means limiting said toggles to semi-straightenedovercenter movement in which position they are held by the energy storedin the flexed equalizer bar.

8. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, a controlmember for said power means, a pair of manuals spaced to require a handof the operator on each for their coincidental actuation, a train ofmechanically connected motion transmitting parts between said manualsand said control member requiring coincidental actuation of both of saidmanuals for effective actuation of said control member, said motiontransmitting parts including a flexible bar which is resilient and ispositioned to be bent transversely by actuation of said control memberand thereby becomes effective in said train for holding said controlmember in actuated position after it is manually moved thereto.

9. In a pressing machine having a pair of coacting pressing members andpower means for causing a pressing operation between them, a controlmember for said power means, a pair of manuals spaced to require a handof the operator on each for their coincidental actuation, a train ofmechanically connected motion transmitting parts between said manualsand said control member requiring coincidental actuation of both of saidmanuals for effective actuation of said control member, said motiontransmitting parts including a flexible bar which is resilient and ispositioned to be stressed transversely by actuation of said controlmember, said train including toggle means between said manuals and saidresilient part adapted to move to an overcenter position and to be thereheld by the stress in said resilient part when it is bent, and saidresilient part together with said toggle means in over-center positionbeing effective to hold said control member in actuated position.

GEORGE W. JOHNSON.

